The invention relates to the field of warning systems in general, and to the area of warning systems that protects linear installations, such as piping systems, railway tracks, electricity lines, fences and the like.
Many linear installations, be it buried ones (for example, piping systems) or above the ground ones (for example, railway tracks, fences along borders), constitute potential targets for sabotage or breaking in through them.
For example, in referring to an example that describes a preferred configuration of the present invention, a typical line for conveying fuel is a linear piping system that in most cases is buried in the ground, for example, 16 to 18 inch diameter pipes buried at 1.5 m to 2 m deep below the ground level and extending in a linear continuum of around 1,500 km in length.
Control of the fuel flow is carried out from several command and control centers, based on one or another data communications system, at times known as SCADA, that arrives from pumping stations located along its length, at a distance of 3 km to 20 km one from each other. Each of these stations is equipped with communication means and a power supply unit where required.
The data transferred by the system includes data relating to the status of the faucets along the route, information about the throughput level and the pressure (preferably if above a pre-set threshold level). Commands for opening/closing the faucets are sent from the command and control centers or stations to the pipelines.
It is to be emphasized once again, that the presented discussion considers only a single example, and that the invention is not limited just for being an application to piping systems buried in the ground, or only used for conveying fuel in the lines. An added example for different linear systems that are also buried in the ground might be a data transmission line or telephone cables.
An act of terror or vandalism damaging the line, or intrusion into the pipe line installations (e.g., one of the control stations), can cause huge and uncontrollable damage. In the fuel line example presented above, sabotage damaging the line might result in cut off of fuel sources at many locations, supply shortages, and even explosions accompanied by injuries or even death of humans as well as sever ecological damage to the environment.
Several activities that might result in damage to linear installation, such as for example a pipeline (fuel, gas), should be considered. They can be divided into several groups. Three essential ones result from human actions, and one can rightly be classified as “natural”. Those that can result from criminal intentions are: drilling into or ruining the pipe in order to steal fuel; act of terror—demolishing the pipe; or a non criminal accident—such as a tractor conducting legal activities too close to pipe lines. “Natural causes” would include deterioration or wear (material fatigue); corrosion; environmental, e g. “activity” of the ground such as earthquakes within a certain range, and the like
At present, there exists no warning or alarm system suitable for protecting linear installations. Thus for example, in accordance with the example presented above, security measures for a fuel pipeline are essentially materialized by manned patrols—both on the ground and aerial ones, that are conducted along the pipeline. Sentries and guards strive to detect any suspicious activities or leaks from the pipelines. However, when patrolling very long lines, it is definitely impossible to cover the total length of the line at a satisfactory frequency, and this fact increases the motivation of terrorists or other intruders to conduct their malicious operations, as they know that the probability of being detected and apprehended is very low. They can, for example, hide at a distance until after the patrol passes, and then accomplish their felonious activities. Even the deployment of electro optical sensors, for example, video cameras, along the length of the line does not provide an adequate solution. Those detectors are expensive, exposed to the environment, burglary and vandalism, and require constant maintenance. Their performance deteriorates under certain detrimental environmental effects such as bad or lowered visibility level (night-time, mist or fog), and they cover very limited sectors and not the entire line.
The throughput data received from the pumping stations deployed along the line might help somewhat, but this “watching” system is calibrated solely to identify catastrophic occurrences, such as an explosion, rupture or cracking of the pipe. The system does not identify small scale local illegal pumping or stealing of fuel, nor does it provide exact information regarding the location of the problem area. In addition, as elicited from its specifications and definitions, it is clear that those existing means being discussed are essentially systems that report about incidents only after they did occur. They do not provide earlier warning messages indicating the would be intrusion or atrocious deed.
An additional type of system that is known in this field is concerned with self-propelled sensors that move along within the flow and detect discontinuities in the line. These sensors, however, are similar in results to those of the manned patrol that passes occasionally along the length of the pipelines, and its weakness, as a system is the outcome of its inherent low frequency operation.
A terror incident or intrusion into linear installations, when it is the result of actions by people naturally requires physical presence. Namely, it requires approaching the installation, i.e., walking or riding towards the installation, excavation in its direction and so on, and then calls for a “penetrating” act such as, for example, excavation, cracking the pipe envelope, severing the barbed wires strands, etc.
Hence, in recent years a solution was proposed, that is based on deploying an optical fiber alongside the length of the linear installation (e.g., the buried pipe line as per the parameters cited above in the example). The optical fiber is sensitive to shifting and vibrations and thus can serve as an indicator of movements along the pipe. When the ability to locate the site of a single event is studied, it is found that the optical fiber is capable of providing an exact indication of the position of the incident. However, a warning system based on optical fibers has many drawbacks, some of which are presented herein. In cases where several incidents occur simultaneously along the line, the system might reach saturation at a level that would prevent the processing of the received data. For example, a tractor working in an agricultural plot bordering on the optical fiber might appear as “an occurrence” of an extremely dominant incident that affects the optical fiber at a specific point and “blinds” the system rendering it incapable of detecting additional, simultaneous incidents in other (far away) locations along the line, that might be several orders of magnitude more dangerous than those that were detected.
An additional drawback stems from the susceptibility of the optical fiber to cuts or impacts. Cutting, severing or disconnecting the fiber—shuts off immediately a long sector of the system and “blinds” it. For example, within a sector of say 30 km long, damaging actions might take place unnoticed, “sponsored” by the break in the fiber's continuity.
A different, additional drawback stems from the fact that the optical fiber—due to its own long continuing construction—might be easily uncovered and exposed. Any clever terrorist or thief is apt to look for the fiber and damage it or disrupt its functioning at the location where it is expected to be found, namely stretched in parallel along the linear installation (as in the fuel pipe line serving as the above example).
An additional drawback of the cited optical fibers system—serving as means for providing warnings triggered by a person approaching the linear installation, such as for example a buried pipe in the ground from a long time past, is the difficulty to upgrade the linear line in order to deploy the fiber along its length. In other words, when a pipe that was buried in the ground a long time ago is considered to be upgraded with such fiber optics based warning system, then excavating it open entails the opening of a wide ditch and exposing the pipe all along its length.
Yet another additional drawback associated with a system that is based on indications resulting from exposing the optical fiber to local movements and/or bending is the inability to identify the exact type of the interference. The same indication might be received due to a herd of innocent cows traversing the line as well as from an intruder excavating towards the line in order to steal fuel.
Finally, at times it is just impossible to obtain the required continuity when deploying the fibers' line, as for example when the pipe line traverses a river or passes over a bridge—where it is exposed to the naked eye, or crossing through a difficult to access wadi or over a boulder/cliff.
It should be pointed out that a physical access to a linear installation and performing a penetrating or piercing activity into it, produce by their inherent nature—acoustic or seismic signals, or in other words—they produce acoustic or seismic “noise”. Put differently, acoustic or seismic noise might constitute an indication to the occurrence of an act of physical approach and/or piercing or penetrating felonious activity on the line.
Sensors that enable the detection of seismic or acoustic interference or noise are known and recognized in the field. It is not sufficient just to detect an interference or noise for providing an effective warning regarding the occurrence of a physical access effort or penetrating action onto or through the linear installation. It is also necessary to determine exactly the accurate point—along the length of the line, at which the malicious activity is in process (while the line might extend, as mentioned, for many kilometers).
Sensing technologies and position locating techniques of targets—that are based on an acoustic sensor (detector) are known and recognized in the field, see for example International Patent application No. WO 01/92846.
Relying on sensing of seismic/acoustic interference and/or noise as an indication to the occurrence of physical access effort and/or penetration action and to the location of this incident, is not an effective one as long as no capability of identification and verification were integrated into the system at a high reliability level that they do not constitute false alarms.
Obviously, routine and innocent activities occurring along the installation line and through the linear system, if they happen to be such that might generate noises or interference, while there is no capability available to identify and verify them and their true nature, might generate false alarm at an undesirable frequency.
To recapitulate, as per the inventor's best knowledge and awareness, at a time preceding the invention and subject matter of this patent application, there was nowhere in existence, a system at a reasonable low price, whose implementation along the linear line would enable detecting, with a high level of confidence, the existence of suspicious or threatening physical approach to the installation and/or penetration/breaking in through its envelope.
On the other hand, it would be desirable to have a system that would provide, simultaneously and accurately, information displaying the exact location of the felonious activity at a high reliability and high confidence levels, regarding the incident in progress. It would be helpful for the system to also supply information on the nature of the occurrence. Moreover, the components of the system should be easy to hide, with the system maintaining its optional performance under all weather conditions and imparting technical and operational advantages (e.g., operability that continues even if one of its components is exposed and destroyed). A further desirable feature would be that the system enable convenient integration into the already existing system of the installation located in the area (for example, as a system to be added on the old pipeline that has been buried in the ground long ago). A system possessing these desirable features is now provided by the present invention.